CN114747299A

CN114747299A - Plasma device

Info

Publication number: CN114747299A
Application number: CN201980102527.6A
Authority: CN
Inventors: 泷川慎二; 神藤高广
Original assignee: Fuji Corp
Current assignee: Fuji Corp
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2022-07-12
Also published as: DE112019008000T5; WO2021130846A1; JP7212801B2; JPWO2021130846A1

Abstract

The invention provides a plasma device capable of notifying corresponding to the generation state of leakage current. The disclosed plasma device is provided with: an electrode that generates plasma by electric discharge; a power supply device that generates electric power to be supplied to the electrodes; a power cable for supplying power from the power supply device to the electrode; a leakage detection device that detects a leakage current of the power cable; and a control device that executes a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and executes a second notification based on a result of comparing the leakage current with a second threshold value.

Description

Plasma device

Technical Field

The present disclosure relates to a plasma apparatus.

Background

Conventionally, various plasma apparatuses have been proposed in which electric power is supplied to an electrode to generate electric discharge, and plasma is generated by the generated electric discharge. The plasma apparatus of patent document 1 includes a vacuum gauge for detecting a pressure in a processing chamber in which plasma is generated. The plasma apparatus changes the flow rate of the plasma generating gas supplied to the processing chamber based on the detection result of the vacuum gauge.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2004-79453

Disclosure of Invention

Problems to be solved by the invention

However, in such a plasma device, if a leakage current flowing from a power cable supplying power to the electrode to the ground is detected by the leakage current detection device, it is possible to detect a power abnormality caused by the leakage current. On the other hand, for example, when high-voltage power is supplied by a power cable to generate plasma, noise is generated even when normal plasma is generated, and the leakage current detection device may detect a leakage current.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a plasma device capable of notifying a generation state of a leakage current in accordance with the generation state.

Means for solving the problems

The present specification discloses a plasma device including: an electrode that generates plasma by electric discharge; a power supply device that generates electric power to be supplied to the electrodes; a power cable for supplying the power from the power supply device to the electrode; an electric leakage detection device that detects an electric leakage current of the electric power cable; and a control device that executes a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and executes a second notification based on a result of comparing the leakage current with a second threshold value

Effects of the invention

According to the present disclosure, the control device performs different notifications according to a result of comparing the leakage current with the first threshold value and a result of comparing the leakage current with the second threshold value. This makes it possible to notify the occurrence of the leakage current in accordance with the occurrence of the leakage current.

Drawings

Fig. 1 is a diagram showing a plasma apparatus.

Fig. 2 is a perspective view of a plasma head.

Fig. 3 is a cross-sectional view of the plasma head cut along the X direction and the Z direction at the positions of the electrode and the main body side plasma passage.

Fig. 4 is a sectional view taken along line a-a of fig. 3.

Fig. 5 is a block diagram showing the structure of the plasma apparatus.

Fig. 6 is a block diagram showing the configuration of the electrical leakage detection device.

Fig. 7 is a block diagram showing the configurations of the current sensor 111 and the gas supply unit 15B.

Fig. 8 is a diagram showing conditions for detecting an abnormality and contents of notification processing in the case of detection.

Fig. 9 is a graph showing a relationship between the leak detection value and each threshold value in a normal state.

Fig. 10 is a graph showing a relationship between the leak detection value and each threshold value in the abnormal state.

Fig. 11 is a graph showing a relationship between the leak detection value and each threshold value in the abnormal state.

Fig. 12 is a graph showing changes in the pressure value of the process gas.

Detailed Description

Hereinafter, one embodiment of carrying out the present disclosure will be described in detail with reference to the drawings. As shown in fig. 1, the plasma device 10 of the present embodiment includes: a plasma head 11, a robot 13 and a control box 15. The plasma head 11 is detachably attached to the distal end of the robot 13. The robot 13 is, for example, a serial link type robot (may also be referred to as an articulated robot). The plasma head 11 can irradiate the plasma gas in a state of being attached to the front end of the robot 13. The plasma head 11 moves by driving the robot 13, changes its orientation, and can move three-dimensionally.

The control box 15 is mainly configured by a computer, and collectively controls the plasma apparatus 10. The control box 15 includes a power supply unit 15A for supplying power to the plasma head 11 and a gas supply unit 15B for supplying a process gas to the plasma head 11. The power supply unit 15A is connected to the plasma head 11 via a power cable 16 and a control cable 18. The power supply unit 15A generates electric power to be supplied to the electrode 33 (see fig. 3) of the plasma head 11 based on the control of the control box 15, and controls the control of changing the voltage applied to the electrode 33 and the temperature of a heater 43 (see fig. 4) described later.

The gas supply unit 15B is connected to the plasma head 11 via a plurality of (4 in the present embodiment) gas supply pipes 19. The gas supply unit 15B supplies a reaction gas (an example of a process gas), a carrier gas (an example of a process gas), and a heating gas (an example of a process gas), which will be described later, to the plasma head 11 under the control of the control box 15. The control box 15 controls the gas supply unit 15B, and controls the amount of gas supplied from the gas supply unit 15B to the plasma head 11. The plasma apparatus 10 operates the robot 13 under the control of the control box 15, and irradiates the object W placed on the stage 17 with plasma gas from the plasma head 11.

The control box 15 includes an operation unit 15C having a touch panel or various switches. The control box 15 displays various setting screens, operation states (for example, gas supply states, etc.), and the like on the touch panel of the operation unit 15C. The control box 15 receives various information by operation input to the operation unit 15C.

The plasma head 11 is detachably mounted on a mounting plate 13A provided at the front end of the robot 13. This enables the plasma head 11 to be replaced with a different type of plasma head 11. As shown in fig. 2, the plasma head 11 includes a plasma generating portion 21, a heated gas supply portion 23, a nozzle 35, and the like. The plasma generator 21 generates a plasma gas by converting the process gas supplied from the gas supply unit 15B (see fig. 1) of the control box 15 into plasma. The plasma head 11 generates a heated gas by heating the process gas supplied from the gas supply unit 15B by a heater 43 (see fig. 4) provided therein. The temperature of the heating gas is, for example, 600 to 800 ℃. The plasma head 11 of the present embodiment discharges the plasma gas generated in the plasma generating portion 21 together with the heated gas to the object W to be processed shown in fig. 1. The process gas is supplied to the plasma head 11 from the upstream side to the downstream side in the direction of the arrow shown in fig. 2. The plasma head 11 may not include the heater 43 for heating the heating gas. That is, the plasma apparatus of the present disclosure may be configured without using a heating gas.

As shown in fig. 2, an attachment portion 11B for attaching the power cable 16 is provided substantially at the center of the connection surface 11A of the plasma head 11. An attachment portion 11C to which the control cable 18 is attached is provided at one end of the connection surface 11A. A mounting portion 11D to which the gas supply pipe 19 is attached is provided on the opposite side of the mounting portion 11C with the mounting portion 11B interposed therebetween. The mounting portion 11D is connected to a mounting member 25 provided at the tip of the gas supply pipe 19, for example. The mounting portion 11D and the mounting member 25 are, for example, so-called one-touch type joints, and the gas supply pipe 19 is detachably mounted to the plasma head 11.

As shown in fig. 3 and 4, the plasma generating portion 21 includes a head main body portion 31, a pair of electrodes 33, a nozzle 35, and the like. Fig. 3 is a cross-sectional view taken at a position corresponding to the pair of electrodes 33 and a plurality of main body-side plasma channels 71 described later, and fig. 4 is a cross-sectional view taken along line a-a of fig. 3. The head body 31 is formed of a ceramic having high heat resistance, and a reaction chamber 37 for generating a plasma gas is formed inside the head body 31. The pair of electrodes 33 are each formed in a cylindrical shape, for example, and fixed in a state in which the tip end portion thereof protrudes into the reaction chamber 37. In the following description, the pair of electrodes 33 may be simply referred to as the electrodes 33. The direction in which the pair of electrodes 33 are arranged is referred to as the X direction, the axial direction of the columnar electrode 33 is referred to as the Z direction, and the direction orthogonal to the X direction and the Z direction is referred to as the Y direction.

The heated gas supply unit 23 includes a gas pipe 41, a heater 43, a connection unit 45, and the like. The gas pipe 41 and the heater 43 are attached to the outer peripheral surface of the head main body 31 and covered with a cover 47 shown in fig. 4. The gas pipe 41 is connected to the gas supply unit 15B of the control box 15 via a gas supply pipe 19 (see fig. 1). A heating gas (e.g., air) is supplied from the gas supply portion 15B to the gas pipe 41. The heater 43 is installed in the middle of the gas pipe 41. The heater 43 heats the heating gas flowing through the gas pipe 41 to generate a heating gas. The heater 43 is provided with a thermocouple 92 (see fig. 5) for detecting the heating temperature of the heater 43.

As shown in fig. 4, the connection portion 45 connects the gas pipe 41 to the nozzle 35. In a state where the nozzle 35 is attached to the head body 31, the connecting portion 45 has one end connected to the gas pipe 41 and the other end connected to the heated gas passage 51 formed in the nozzle 35. The heated gas is supplied to the heated gas passage 51 through the gas pipe 41.

As shown in fig. 3 and 4, the outer periphery of a part of the electrode 33 is covered with an electrode cover 53 made of an insulator such as ceramic. The electrode cover 53 has a substantially hollow cylindrical shape, and has openings formed at both ends in the longitudinal direction. The gap between the inner peripheral surface of the electrode cover 53 and the outer peripheral surface of the electrode 33 functions as a gas passage 55. The opening on the downstream side of the electrode cover 53 is connected to the reaction chamber 37. The lower end of the electrode 33 protrudes from the opening on the downstream side of the electrode cover 53.

Further, a reaction gas passage 61 and a pair of carrier gas passages 63 are formed inside the head main body 31. The reaction gas flow path 61 is provided in a substantially central portion of the head main body portion 31, is connected to the gas supply portion 15B via the gas supply pipe 19 (see fig. 1), and allows the reaction gas supplied from the gas supply portion 15B to flow into the reaction chamber 37. The pair of carrier gas channels 63 is disposed at a position in the X direction so as to sandwich the reaction gas channel 61. The pair of carrier gas flow paths 63 are connected to the gas supply unit 15B via each of the pair of gas supply pipes 19 (see fig. 1), and the carrier gas is supplied from the gas supply unit 15B. The carrier gas passage 63 allows the carrier gas to flow into the reaction chamber 37 through the gas passage 55. The 4 gas supply pipes 19 shown in fig. 1 and 2 are, for example, 2 gas supply pipes 19 for supplying a carrier gas to the pair of carrier

gas flow paths

63, 1 gas supply pipe 19 for supplying a reaction gas, and a gas supply pipe 19 for supplying a heating gas (a heating gas before heating).

As the reaction gas (seed gas), oxygen (O) can be used₂). The gas supply unit 15B, for example, supplies oxygen gas and nitrogen gas (N) through the reaction gas flow path 61₂) The mixed gas (e.g., dry Air (Air)) of (a) flows between the electrodes 33 of the reaction chamber 37. Hereinafter, for convenience, the mixed gas may be referred to as a reaction gas, and the oxygen gas may be referred to as a seed gas. As the carrier gas, nitrogen gas may be used. The gas supply portion 15B causes the carrier gas to flow from each gas passage 55 so as to surround each electrode 33 of the pair of electrodes 33.

An ac voltage is applied from the power supply unit 15A of the control box 15 to the pair of electrodes 33. By applying a voltage, for example, as shown in fig. 3, a simulated arc a is generated between the lower ends of the pair of electrodes 33 in the reaction chamber 37. The simulated arc a is a method in which, for example, a large current does not flow as in a normal arc discharge, and the power supply unit 15A discharges the arc while limiting the current. When the reaction gas passes through the simulated arc a, the reaction gas is converted into plasma. Therefore, the pair of electrodes 33 generates electric discharge simulating the arc a to turn the reaction gas into plasma, thereby generating a plasma gas.

In addition, a plurality of (6 in the present embodiment) main body side plasma passages 71 are formed in a portion of the head main body portion 31 on the downstream side of the reaction chamber 37. The upstream ends of the plurality of main body side plasma paths 71 are open to the reaction chamber 37, and the downstream ends of the plurality of main body side plasma paths 71 are open to the lower end surface of the head main body 31.

The nozzle 35 is formed of, for example, ceramics having high heat resistance. The nozzle 35 is fixed to the lower surface of the head body 31 by a bolt 80. Therefore, the nozzle 35 can be attached to and detached from the head body 31, and can be changed to a different type of nozzle. The nozzle 35 is formed with a pair of grooves 81 having an opening formed in an upper end surface. The pair of grooves 81 communicate with, for example, 3 main body side plasma passages 71 that are open at the lower end surface of the head main body 31. Further, the nozzle 35 is formed with a plurality of (10 in the present embodiment) nozzle-side plasma passages 82 penetrating in the Z direction. Grooves 81 (for example, 5 each) are connected to the upper end of the nozzle-side plasma passage 82. The shape and structure of the nozzle 35 shown in fig. 3 and 4 are examples.

Further, a heating gas passage 95 is formed in the nozzle 35 so as to surround the nozzle-side plasma passage 82. The upper portion of the heated gas passage 95 is connected to the connection portion 45 of the heated gas supply unit 23 via the heated gas passage 51. The lower end of the heating gas passage 95 opens to the lower surface of the nozzle 35.

With this configuration, the plasma gas generated in the reaction chamber 37 is ejected into the groove 81 through the main body-side plasma passage 71 together with the carrier gas. Then, the plasma gas diffuses inside the groove 81, and is ejected from the opening 82A at the lower end of the nozzle-side plasma passage 82 through each of the plurality of nozzle-side plasma passages 82. The heated gas supplied from the gas pipe 41 to the heated gas passage 51 flows through the heated gas passage 95. The heated gas functions as a shield gas for shielding the plasma gas. The heating gas flows through the heating gas passage 95, and is ejected from an opening 95A at the lower end of the heating gas passage 95 along the ejection direction of the plasma gas. At this time, the heating gas is ejected so as to surround the plasma gas ejected from the opening 82A of the nozzle-side plasma passage 82. By thus ejecting the heated gas to the periphery of the plasma gas, the efficiency (wettability, etc.) of the plasma gas can be improved.

Next, a detailed configuration of the control box 15 will be described. As shown in fig. 5, the control box 15 includes a controller 100, a drive circuit 105, a control circuit 106, a communication unit 107, a leakage detecting device 110, a current sensor 111, a storage device 116, and the like, in addition to the power supply unit 15A, the gas supply unit 15B, and the operation unit 15C described above. The controller 100 is mainly configured by a computer including a CPU, ROM, RAM, and the like, which are not shown. The controller 100 executes a program by the CPU to control the power supply unit 15A, the drive circuit 105, the gas supply unit 15B, and the like, thereby controlling the plasma head 11, the heating gas supply unit 23, and the like. The controller 100 that executes the program by the CPU may be described by a device name alone. For example, the description "controller 100" may mean "controller 100 that executes a program by CPU".

The controller 100 is connected to the operation unit 15C via the control circuit 106. The controller 100 changes the display of the touch panel of the operation unit 15C via the control circuit 106. Further, the controller 100 receives an operation input to the operation unit 15C via the control circuit 106. The storage device 116 is configured by combining a hard disk drive, a RAM, a ROM, and the like. The storage device 116 stores state information 118. The controller 100 stores, for example, information on the state of the plasma apparatus 10, information when an abnormality is detected, setting information of the plasma apparatus 10, an operation time of each device, and the like as the state information 118.

The communication unit 107 communicates with a communication device connected to a network, not shown. The communication method is not particularly limited, and examples thereof include LAN and serial communication. The controller 100 may store the state information 118 in a server device or the like on the network via the communication unit 107, instead of the storage device 116 in the control box 15.

The leakage detecting device 110 is a device that detects a leakage current of the power cable 16 connecting the power supply unit 15A and the plasma head 11 (electrode 33). Fig. 6 shows the structure of the electrical leakage detection device 110. As shown in fig. 6, the power cable 16 of the present embodiment includes, for example, a first cable 16A, a second cable 16B, and a ground cable 16C. The distal ends of the first cable 16A and the second cable 16B are electrically connected to a pair of electrodes 33 (see fig. 3) provided in the plasma head 11. As shown in fig. 1, the power cable 16 is attached to the robot 13. Therefore, a load such as bending, rotation, or tension may be applied to the power cable 16 according to the operation of the robot 13, and the power cable may be damaged. Therefore, the plasma device 10 of the present embodiment detects an abnormal current generated by damage or the like of the power cable 16 by the leakage detecting device 110.

As shown in fig. 6, the electrical leakage detection device 110 includes: a detection module 120 and a current transformer CT. The detection module 120 has a comparison circuit 121 and a power circuit 122. The first cable 16A, the second cable 16B, and the ground cable 16C of the power cable 16 are each covered with an insulator, for example, on an electric wire. The first cable 16A, the second cable 16B, and the ground cable 16C are shielded by a mesh-like conductive shielding member 145. The shielding member 145 is grounded via the ground cable 16C.

The power supply unit 15A includes

AC power supplies

141 and 142. The AC power supply 141 generates AC power having a predetermined voltage value and a predetermined current value based on power supplied from a commercial power supply (not shown). The AC power supply 141 supplies the generated AC power to each of the pair of electrodes 33 via the first cable 16A and the second cable 16B.

The current transformer CT of the electrical leakage detection apparatus 110 is attached to the ground cable 16C. The current transformer CT outputs a detection voltage corresponding to the current value of the leakage current flowing through the ground cable 16C to the comparator circuit 121. The AC power supply 142 generates, for example, AC power (for example, AC200V) to be supplied to the power supply circuit 122 from the AC power supplied from the AC power supply 141. The power supply circuit 122 outputs the drive voltage and the threshold voltage supplied to the comparator circuit 121 based on the AC power supplied from the AC power supply 142, and supplies the generated drive voltage and threshold voltage to the comparator circuit 121. The threshold voltage is an example of the first threshold value and the second threshold value of the present disclosure.

The comparator circuit 121 compares the detection voltage of the current transformer CT with a threshold voltage, and outputs detection information SI indicating the comparison result to the controller 100. Here, when a short circuit or discharge occurs between the first cable 16A or the second cable 16B and the ground cable 16C, a leakage current flows from the AC power supply 141 to the ground. Therefore, the detection voltage of the current transformer CT fluctuates. The comparison circuit 121 outputs the result of comparing the detection voltage of the varying current transformer CT with the threshold value to the controller 100 as the detection information SI.

When a short circuit or a discharge occurs between the first cable 16A and the second cable 16B, a leakage current flows through the shield member 145 due to electromagnetic induction or the like. In this case, the comparison circuit 121 also outputs the result of comparing the detection voltage of the current transformer CT that fluctuates with the threshold value to the controller 100 as the detection information SI. As described above, leakage detecting device 110 can detect not only the ground of first cable 16A or second cable 16B but also a short circuit or discharge between first cable 16A and second cable 16B.

In addition, when the power supply in which the short circuit or the discharge does not occur, that is, in a normal state in which the power cable 16 supplies power necessary for the plasma generation control without causing damage or disconnection of the power cable 16, a leakage current flows through the shield member 145 by electromagnetic induction or the like. In addition, when some noise is input to the shield member 145, a leakage current may be generated. Even in such a normal state or in a case other than the abnormality of the plasma device 10, the leakage detecting device 110 outputs the comparison result using the threshold value to the controller 100 as the detection information SI.

The configuration of the electrical leakage detection device 110 is not particularly limited. For example, the leakage current detection device 110 may be configured to compare a current value of a leakage current flowing through the ground cable 16C with a threshold value. For example, the leakage detecting device 110 AD-converts a detection voltage corresponding to a current value flowing to the first cable 16A and the second cable 16B detected by the current transformer, and outputs a digital value indicating the current value to the controller 100. The controller 100 may also compare the inputted current value with a threshold value. That is, the leakage detecting device of the present disclosure may be configured to compare current values. In this case, a predetermined current value can be set as the first threshold value and the second threshold value of the present disclosure. The controller 100 may perform a comparison process between the detected voltage value and current value and a threshold value. In this case, the controller 100 is an example of the leakage detecting device of the present disclosure.

The controller 100 of the present embodiment determines an abnormality of the apparatus based on the pressure value of the process gas in addition to the detection information SI for detecting the leakage current. As shown in fig. 7, the gas supply unit 15B includes a gas generation device 109, a plurality of mass flow controllers 112 (F1 to F5 in fig. 7), a plurality of pressure sensors 113 (white four corners in the figure), and the like. The gas generator 109 is a device for supplying a reaction gas, a carrier gas, and a heating gas. The gas generator 109 is supplied with, for example, nitrogen (N)₂) Oxygen (O)₂) Air (Air, dry Air, etc.). The gas generator 109 includes a compressor serving as a supply source of air, and removes the air supplied from the compressorA dryer for the moisture, a separation device for separating nitrogen and oxygen from the dry air, etc. The gas generator 109 may use air containing oxygen or dry air as the oxygen of the seed gas of the reaction gas.

The gas generator 109 supplies a reaction gas (oxygen gas, nitrogen gas), a carrier gas (nitrogen gas), and a heating gas (air) as process gases. The mass flow controllers 112 are provided, for example, in correspondence with the respective process gases, and control the flow rates of the respective process gases based on the control of the controller 100. Each mass flow controller 112 outputs the value (measured value) of the adjusted actual supplied flow rate to the controller 100.

The pressure sensors 113 detect the pressure value of the process gas whose flow rate is adjusted by each mass flow controller 112. The pressure sensor 113 detects a pressure value of a mixed gas in which the reaction gases (oxygen and nitrogen) are mixed in the mixer 115. Therefore, the pressure sensor 113 detects oxygen (O) as a reaction gas (seed gas)₂) Nitrogen (N) mixed with oxygen₂) And the pressure of the mixed gas (dry air) after mixing. The pressure sensor 113 detects the pressure of the carrier gas flowing through the gas supply pipe 19 connected to each of the pair of carrier gas flow paths 63. The pressure sensor 113 detects the pressure value of the heating gas (air before heating) supplied to the gas pipe 41. Each pressure sensor 113 outputs the detected pressure value to the controller 100. The controller 100 of the present embodiment determines an abnormality of the apparatus based on the leakage current (detection voltage) and the pressure value of the process gas. The content of the determination process will be described later.

The power supply unit 15A generates high-frequency ac power to be supplied from the commercial power supply to the electrode 33, and supplies the generated ac power to the electrode 33. The current sensor 111 detects a current flowing through the first cable 16A and the second cable 16B for supplying power from the power supply unit 15A to the electrode 33. The current sensor 111 includes, for example, a current transformer, AD-converts a detection voltage corresponding to a current value flowing through the first cable 16A and the second cable 16B detected by the current transformer, and outputs a digital value corresponding to the current value to the controller 100.

As shown in fig. 5, the heater 43 and the thermocouple 92 attached near the heater 43 are electrically connected to the drive circuit 105. The drive circuit 105 outputs a temperature corresponding to the output value of the thermocouple 92 to the controller 100. The drive circuit 105 controls the heating temperature of the heater 43 so as to be the target temperature instructed by the controller 100 based on the output value of the thermocouple 92. The temperature sensor 114 is provided, for example, in the plasma head 11. The temperature sensor 114 has, for example, a thermocouple, detects the temperature of the plasma gas, and outputs the detected temperature to the controller 100.

Next, a notification process executed by the controller 100 of the present embodiment will be described. The controller 100 starts the plasma generation control when receiving an instruction to start the plasma processing via the touch panel of the operation unit 15C, for example. In the plasma generation control, the controller 100 causes the power supply unit 15A to start control for supplying a predetermined electric power to the electrode 33. In the following description, the case where the power supply from the power supply unit 15A to the electrode 33 is started will be referred to as "plasma ON".

When the plasma is ON, the controller 100 causes the gas supply unit 15B to start supplying the process gas (carrier gas, reaction gas, heating gas). The gas supply unit 15B starts supply of the process gas at a predetermined gas flow rate and a predetermined pressure value. The controller 100 controls the drive circuit 105 to control the heating temperature of the heater 43 so as to be a predetermined temperature.

Further, when the plasma is ON, the controller 100 stores state information 118 relating to the state of the plasma apparatus 10 in the storage device 116. In addition, the controller 100 determines the occurrence of an abnormality of the apparatus. When an abnormality of the apparatus is detected, the controller 100 stops the supply of the electric power to the electrode 33, stops the supply of the process gas, stops the operation of the heating gas supply unit 23, and ends the plasma generation control. Thereby, the plasma generation of the plasma device 10 is stopped. When an abnormality is detected and the plasma generation control is ended, the controller 100 causes the screen of the operation unit 15C to display information of the detected abnormality.

Fig. 8 shows a condition under which the controller 100 determines that there is an abnormality and the contents of the notification processing in a case where the abnormality is detected. In the following description, the detection voltage value detected by the leakage detecting device 110 will be referred to as a leakage detection value. First, the top No. 1 indicates a case where the leakage detection value detected by the leakage detection device 110 is equal to or greater than the maximum threshold TH 1. The second 2 is a case where the leakage detection value detected by the leakage detection device 110 is equal to or greater than the upper threshold TH 2. Fig. 9 shows the relationship between the leak detection value and each threshold value in the normal state. The controller 100 of the present embodiment determines an abnormality in the leakage detection value using the maximum threshold TH1, the upper threshold TH2, the lower threshold TH3, and the minimum threshold TH 4.

The maximum threshold TH1 is a value that can determine a detection value of leakage (a detection voltage value corresponding to leakage current) detected when, for example, the power cable 16 is cut or damaged and a short circuit or a discharge occurs between the first cable 16A or the second cable 16B and the ground cable 16C. The maximum threshold TH1 is, for example, a voltage value applied to the electrode 33 at the time of discharge or a value obtained by subtracting a power loss of the power cable 16 or the ground cable 16C from the voltage value. The upper threshold TH2 is a value smaller than the maximum threshold TH 1. For example, when a short circuit or discharge occurs between the first cable 16A and the second cable 16B, or when a slight disconnection or the like of the power cable 16 occurs, a leakage current flows through the shield member 145 due to electromagnetic induction or the like. The upper limit threshold TH2 is a value capable of detecting an increase (abnormality) in the leak detection value that has not increased to such a maximum threshold TH 1. As shown by a solid-line waveform 150 in fig. 9, when the power cable 16 is not damaged or cut and the power supply can be performed normally, the detection value of the leakage current gradually increases from the plasma ON time, for example, and becomes stable near the reference value Vs. The reference value Vs is a leakage detection value generated by electromagnetic induction, noise, and the like during normal power supply.

On the other hand, fig. 10 shows the relationship between the leak detection value and each threshold value in the abnormal state. The dashed waveform 151 indicates a case where the leak detection value is equal to or greater than the upper limit threshold TH2, and indicates a case where the leak detection value increases due to occurrence of some abnormality from a state where the leak detection value is stable at the reference value Vs. As shown by the waveform 151, when discharge or the like occurs between the first and

second cables

16A, 16B in a state where the leakage detection value is the reference value Vs (for example, during plasma irradiation), the leakage detection value increases from the reference value Vs to be equal to or higher than the upper limit threshold TH 2. For example, when the first and

second cables

16A and 16B are not completely cut off, only a part of the electric power supplied from the power supply unit 15A flows to the ground cable 16C, and the leakage detection value does not increase to the maximum threshold TH1 and becomes smaller than the maximum threshold TH 1. Similarly to the case where an abnormality occurs after plasma ON, for example, when the power cable 16 is damaged before plasma ON, the leakage detection value increases to the upper limit threshold TH2 or more after plasma ON.

When detecting that the leakage detection value is equal to or greater than the upper threshold TH2, the controller 100 displays on the touch panel of the operation unit 15C that the power cable 16 may be cut, as shown in fig. 8. As described above, the upper limit threshold TH2 is a threshold for warning when an increase in the detected value of electrical leakage is detected for some reason, although it is unclear whether the power cable 16 is actually cut. Therefore, the controller 100 displays a confirmation message such as "please confirm because damage may occur somewhere on the power cable 16" on the operation unit 15C. Then, for example, the user confirms the state of the plasma apparatus 10 and performs an operation input to the operation unit 15C to indicate that confirmation has been completed. The controller 100 may restart the plasma generation control when receiving an operation input to the operation unit 15C.

On the other hand, a solid-line waveform 153 in fig. 10 indicates a case where the leak detection value is equal to or greater than the maximum threshold value TH 1. As shown by the waveform 153, when the power cable 16 is cut or the like in a state where the leakage detection value is the reference value Vs, the leakage detection value increases from the reference value Vs and exceeds the upper limit threshold TH2 to become the maximum threshold TH1 or more. For example, when a short circuit occurs between the first cable 16A and the ground cable 16C, most of the electric power supplied from the AC power supply 141 to the first cable 16A flows to the ground as a leakage current via the ground cable 16C. Therefore, the possibility that the leak detection value increases to the maximum threshold value TH1 becomes high. Similarly, for example, when the power cable 16 is cut off from before plasma ON, the leakage detection value also increases to the maximum threshold TH1 after plasma ON.

When detecting that the leakage detection value is equal to or greater than the maximum threshold value TH1, the controller 100 displays on the touch panel of the operation portion 15C the fact that the power cable 16 is cut as shown in fig. 8. As described above, when the leakage detection value is equal to or greater than the maximum threshold value TH1, the possibility of occurrence of disconnection or the like of the power cable 16 is extremely high. Therefore, the controller 100 displays a warning message such as "emergency stop due to damage occurring somewhere on the power cable 16" on the operation unit 15C. In this case, the controller 100 stops the power supply of the power supply unit 15A until the cause of the leakage abnormality is reliably solved, for example, when replacement of the power cable 16 is detected, or when an operation input confirmed by a maintenance worker through the operation unit 15C is made.

Therefore, in the present embodiment, the first threshold includes an upper limit threshold TH2 larger than a leakage detection value (a current value of the leakage current, a current value corresponding to the reference value Vs) detected by the leakage detection device 110 in a state where plasma is normally generated. In addition, as the second threshold, a maximum threshold TH1 larger than the upper limit threshold TH2 is included. When the leakage detection value becomes equal to or greater than the upper threshold TH2, the controller 100 notifies the power cable 16 of the possibility of leakage (an example of the first notification). When the current value of the leakage current becomes equal to or greater than the maximum threshold TH1, the controller 100 notifies the disconnection of the power cable 16 (an example of the second notification).

An upper threshold TH2 is set to a leakage current (reference value Vs) based on noise (induced current) generated by power supply in a state where plasma is normally generated, and the like, which is larger than the leakage current. This makes it possible to notify the possibility of electrical leakage such as a short circuit of the power cable 16. By setting the maximum threshold value TH1 larger than the upper threshold value TH2, it is possible to detect and notify a state in which the occurrence of an abnormal leakage is extremely high, such as a case in which the power cable 16 is completely cut and abnormal discharge occurs in the middle of the power cable 16. Therefore, by the upper limit threshold TH2 and the maximum threshold TH1, the possibility of electric leakage and the reliable notification of electric leakage can be performed.

Note that No. 3 and No. 4 in fig. 8 indicate the case where the leak detection value is equal to or less than the minimum threshold TH 4. The controller 100 of the present embodiment determines an electrical leakage abnormality based ON the lowest threshold TH4 when plasma is ON. The lowest threshold TH4 is, for example, a threshold for detecting an abnormality in which a leakage current does not flow (a leakage detection value does not increase) or the leakage current is extremely small. For example, when a failure occurs in the leakage detection device 110, such as when the grounding cable 16C is forgotten to be connected to the ground of the plasma apparatus 10, when the grounding cable 16C is disconnected, or when the grounding cable 16C is disconnected, there is a possibility that the leakage detection value will not increase or become extremely small. The lowest threshold TH4 is a value that can detect such a state where the leak detection value does not increase, and is, for example, 0V (0A if current) or a value close to 0V.

Waveform 155 in fig. 11 indicates a case where the detected leakage value is equal to or less than minimum threshold TH4, and indicates a state when plasma is ON. As shown by the waveform 155, when forgetting to attach the ground cable 16C or the like occurs, the leakage detection value is lower than the lowest threshold TH4 or is lower than the lower threshold TH3 described later and is in the vicinity of the lowest threshold TH4 without increasing from the time of plasma ON.

On the other hand, even when the ground cable 16C is normally connected, for example, when the process gas is not supplied and the discharge of the electrode 33 is not generated, or when the discharge is not generated for some reason, there is a possibility that the leak detection value does not increase. Specifically, there is a possibility that the detection value of the leakage current may be lowered due to various causes such as damage to the gas supply pipe 19, failure of the gas supply unit 15B, deterioration of the electrode 33, and damage to the reaction chamber 37.

Fig. 12 shows changes in the pressure value of the process gas from the plasma ON time to the plasma irradiation time. Here, for example, as long as no abnormality occurs in the generation state of the pseudo arc a or the like in the pressure value of the process gas detected by the pressure sensor 113, the pressure value increases in the same manner as the pressure value of the process gas during the period after plasma ignition and plasma irradiation start from the plasma ON time regardless of the types of the carrier gas, the reaction gas, and the heating gas. Therefore, in the following description, various gases will be collectively referred to as process gases unless particularly distinguished. As shown by a waveform 157 in fig. 12, the pressure value of the pressure of the process gas whose flow rate and flow rate have been adjusted by the adjustment of the mass flow controller 112, which is detected by the pressure sensor 113, gradually increases from the plasma ON time. Since the supply of each process gas is started from the time of plasma ON, the pressure value gradually increases. The pressure value is saturated at, for example, the reference pressure value Ps. Then, the pseudo arc a is generated between the electrodes 33, and the temperature of the plasma head 11 rises. In addition, the temperature of the plasma head 11 is also increased by heating the heating gas. The pressure value gradually increases from the reference pressure value Ps with the passage of time.

When the gas supply pipe 19 is damaged or the gas supply portion 15B fails, the pressure value decreases as shown by a waveform 159 of a broken line in fig. 12. The degree to which the pressure value is reduced depends on the time point at which the abnormality occurs, the type and scale of the abnormality that occurs, and the like. For example, if the pressure value is decreased before plasma ignition, there is a possibility that the pressure value does not increase to the reference pressure value Ps (see the lower waveform 159). Alternatively, if the pressure value is decreased after plasma ignition, there is a possibility that the pressure value will not increase to the predetermined threshold pressure value Pth (see the upper waveform 159). The threshold pressure value Pth is, for example, a threshold value set between the reference pressure value Ps and the maximum pressure value at the time of plasma irradiation. Therefore, by setting the reference pressure value Ps and the threshold pressure value Pth in advance, an abnormality in which the pressure value does not rise can be detected.

Therefore, as shown in fig. 8, when the controller 100 detects that the leakage detection value is equal to or less than the minimum threshold value TH4 and the pressure value does not rise to the reference pressure value Ps, for example, at the time of plasma ON, the operation unit 15C indicates that plasma is not irradiated. The plasma ON time here means, for example, a period from plasma ON to plasma ignition. Alternatively, the plasma ON time may be a period from the plasma ON to the stable irradiation of the plasma gas. The non-plasma irradiation is not only intended to notify an abnormality that no plasma is generated, but also to notify an abnormality other than the abnormality related to the leakage detection device 110, such as damage to the gas supply pipe 19, failure of the gas supply unit 15B, deterioration of the electrode 33, and damage to the reaction chamber 37. ON the other hand, as shown in fig. 8 No. 4, when the controller 100 detects that the leakage current detection value is equal to or less than the minimum threshold value TH4 and the pressure value is increased to or higher than the reference pressure value Ps (increased to a normal value) at the time of plasma ON, the operation unit 15C indicates that there is an abnormality (an example of an abnormality related to the leakage current detection device 110) in the ground cable 16C and the shield member 145.

Note that No. 5 and No. 6 in fig. 8 indicate the case where the leak detection value is equal to or less than the lower limit threshold TH 3. The controller 100 of the present embodiment determines an electrical leakage abnormality based on the lower threshold TH3 after the start of plasma irradiation. The period after the start of plasma irradiation is, for example, a period after plasma ignition. Alternatively, the period after the start of the plasma irradiation may be a period after the state in which the plasma gas is stably irradiated. The lower threshold TH3 is smaller than a reference value Vs at which normal plasma irradiation can be performed without occurrence of the above-described various abnormalities, and is larger than the lowest threshold TH 4. For example, the upper threshold TH2 is a value obtained for a reference value Vs + X [ V ]. The lower threshold TH3 is a value obtained for a reference value Vs-X [ V ]. That is, the upper threshold TH2 and the lower threshold TH3 are, for example, values obtained by adding or subtracting a predetermined value (X [ V ]) to or from the reference value Vs as a center value.

Similarly to the lowest threshold TH4, when a leakage abnormality occurs after the plasma irradiation is started, there is a possibility that the leakage detection value decreases. In addition, when the gas supply pipe 19 is damaged after the plasma irradiation is started, or when the supply of the process gas is stopped, the detection value of the leakage current may be lowered (see a waveform 161 of a broken line in fig. 9). Therefore, as shown in fig. 8, after the start of plasma irradiation, the controller 100 indicates that plasma is not irradiated in the operation portion 15C when it is detected that, for example, the leakage detection value has decreased to the lower limit threshold TH3 or less and the pressure value has decreased to the threshold pressure value Pth (see fig. 12). Thus, when an abnormality such as plasma extinction, damage to the gas supply pipe 19, failure of the gas supply portion 15B, deterioration of the electrode 33, damage to the reaction chamber 37 occurs during plasma irradiation, it is possible to notify the abnormality as plasma irradiation. The controller 100 may determine a decrease in the pressure value from the reference pressure value Ps (see fig. 12). On the other hand, as shown in fig. 6 in fig. 8, when the controller 100 detects that the leakage detection value has decreased to the lower limit threshold TH3 or less and the pressure value has been maintained at the threshold pressure value Pth or more after the start of plasma irradiation, the operation unit 15C indicates that there is an abnormality in the ground cable 16C or the shield member 145 (an example of an abnormality in the leakage detection device 110).

Therefore, in the present embodiment, the first threshold includes a lower threshold TH3 (see fig. 9) smaller than a reference value Vs (a voltage value corresponding to a current value of the leakage current) detected by the leakage detecting device 110 in a state where plasma is normally generated. The second threshold includes a lowest threshold TH4 smaller than the lower threshold TH 3. When the leak detection value is equal to or less than the minimum threshold value TH4 and the pressure value of the process gas detected by the pressure sensor 113 does not increase to a predetermined pressure value (threshold pressure value Pth, reference pressure value Ps) at the time of starting the supply of electric power to the electrode 33 (at the time of plasma ON), the controller 100 notifies an abnormality that the plasma is not irradiated (an example of the second notification). When the electric leakage detection value is equal to or less than the minimum threshold value TH4 and the pressure value of the process gas detected by the pressure sensor 113 has increased to a predetermined pressure value when the electric power supply to the electrode 33 is started, the controller 100 notifies an abnormality related to the electric leakage detection device 110 (an example of the second notification).

When the supply of power to the electrode 33 is started (after plasma ON), the current value of the leakage current exceeds the minimum threshold TH4, for example, from a zero state, and further exceeds the lower threshold TH3, and becomes a normal current value (see the waveform 150 in fig. 9). In other words, by using the lowest threshold TH4 when the supply of electric power is started, an abnormality can be detected earlier than when the lower threshold TH3 is used. Therefore, when the leak detection value is equal to or less than the lowest threshold TH4 and the pressure value does not increase at the start of the supply of electric power, the controller 100 notifies that the plasma is not irradiated abnormally. Thus, when the plasma is not ignited or the process gas is not supplied, the abnormality can be notified. When the electric power supply is started, the controller 100 notifies the leakage detecting device 110 of an abnormality when the detected value of the leakage is equal to or less than the lowest threshold TH4 and the pressure value increases. Thus, when an abnormality such as a connection error of the electrical leakage detection device 110 or disconnection of the ground cable 16C occurs, the abnormality can be notified.

Further, in the plasma irradiation period after the start of the plasma irradiation, when the leak detection value is equal to or less than the lower limit threshold value TH3 and the pressure value of the process gas detected by the pressure sensor 113 is reduced to a predetermined pressure value (threshold pressure value Pth or reference pressure value Ps), the controller 100 notifies an abnormality that no plasma is irradiated (an example of the first notification, No. 5 in fig. 8). Further, the controller 100 notifies an abnormality related to the leakage current detection device 110 when the leakage current detection value is equal to or less than the lower limit threshold TH3 and the pressure value of the process gas detected by the pressure sensor 113 is not reduced to a predetermined pressure value during the plasma irradiation period (an example of the first notification is No. 6 in fig. 8).

When the plasma irradiation is started, the current value and the pressure value of the leakage current are within a certain range. When an abnormality occurs, the current value or the voltage value is lower than the lower threshold TH3, and further lower than the lowest threshold TH 4. In other words, by using the lower threshold TH3 after the start of the plasma irradiation, the abnormality can be detected earlier than in the case of using the lowest threshold TH 4. Therefore, when the leak detection value is equal to or less than the lower threshold TH3 and the pressure value is reduced during plasma irradiation, the controller 100 notifies an abnormality that plasma is not irradiated. Thus, when the plasma is interrupted or the supply of the process gas is stopped, an abnormality can be notified. Further, the controller 100 notifies an abnormality related to the leakage detecting device 110 when the leakage detection value is equal to or less than the lower threshold TH3 and the pressure value is not decreased during the plasma irradiation period. Thus, when an abnormality such as a failure of the leakage detection device 110 or disconnection of the ground cable 16C occurs, the abnormality can be notified.

The controller 100 of the present embodiment performs notification No. 5 and No. 6 (an example of the first notification) and notification No. 3 and No. 4 (an example of the second notification) based on the pressure value of the process gas and the leakage detection value (the voltage value and the current value of the leakage current) detected by the pressure sensor 113. The pressure value detected by the pressure sensor 113 increases at a time point such as the start of the supply of the process gas and the ignition of the plasma. Therefore, the controller 100 determines the occurrence of the leakage current by combining the pressure value of the process gas with the voltage value and the current value of the leakage current, and can thereby distinguish the occurrence in more detail and change the notification content.

The plasma device 10 of the present embodiment includes a conductive shielding member 145 that shields the power cable 16, and a ground cable 16C that grounds the shielding member 145. The leakage detecting device 110 detects a leakage current flowing through the ground cable 16C. Thereby, the leakage current detection device 110 can detect the leakage current flowing from the shielding member 145 of the shielded power cable 16 to the ground. In the shield member 145, there is a possibility that a leakage current flows due to various noises. Therefore, the controller 100 can perform notification corresponding to the generation state of the leakage current by comparing the detected leakage current with the first and second thresholds (the maximum threshold TH1, the upper threshold TH2, the lower threshold TH3, and the minimum threshold TH 4).

Fig. 8 shows an example of processing for notifying an abnormality based on a detected voltage value based on the leak current and a pressure value of the process gas. The controller 100 may also notify an abnormality based on other information (the flow rate of the mass flow controller 112 or the current value detected by the current sensor 111). The controller 100 may determine an abnormality by combining other information in addition to the detected voltage value of the leakage current and the pressure value of the process gas, and may change the notification content. The controller 100 may set each threshold value for the current value of the leakage current to determine the abnormality, similarly to the voltage value of the leakage current.

Incidentally, in the above embodiment, the power supply unit 15A is an example of a power supply device. The gas supply unit 15B is an example of a gas supply device. The carrier gas, the reaction gas, and the heating gas are examples of the process gas. The controller 100 is an example of a control device. The pressure sensor 113 is an example of a pressure detection device. The upper threshold TH2 and the lower threshold TH3 exemplify the first threshold. The maximum threshold TH1 and the minimum threshold TH4 exemplify the second threshold.

As described above, according to the embodiment, the following effects are obtained.

In one embodiment of the present embodiment, the controller 100 of the plasma apparatus 10 executes the notification nos. 2, 5, and 6 (an example of the first notification) shown in fig. 8 based on the result of comparing the leakage detection value detected by the leakage detection device 110 with the first threshold values (the upper threshold value TH2 and the lower threshold value TH 3). Further, the controller 100 executes the notification nos. 1, 3, and 4 based on the result of comparing the leakage detection value with the second threshold value (the maximum threshold value TH1, the minimum threshold value TH4) (an example of the second notification).

Thus, the leakage current of the power cable 16 supplying power to the electrode 33 is monitored by the leakage detecting device 110. The controller 100 performs different notifications according to the result of comparing the leakage current with the first threshold value and the result of comparing the leakage current with the second threshold value. Thus, it is possible to determine the occurrence of a leakage current such as a leakage current caused by noise during normal power supply, a short circuit of the power cable 16, a leakage current caused by disconnection, or a leakage current detected due to a failure in the leakage detecting device 110, using the first and second threshold values, and to perform different notifications. Therefore, notification according to the occurrence of the leakage current can be performed.

It is needless to say that the present disclosure is not limited to the above embodiments, and various improvements and modifications can be made without departing from the scope of the present disclosure.

For example, the controller 100 determines the leakage abnormality using the maximum threshold TH1, the upper threshold TH2, the lower threshold TH3, and the minimum threshold TH4, but is not limited thereto. For example, the controller 100 may determine the leakage abnormality only by a combination of the maximum threshold TH1 and the upper threshold TH2, or only by a combination of the lower threshold TH3 and the lowest threshold TH 4.

Further, the controller 100 may determine the leakage abnormality by using only the first threshold value and the second threshold value without using the pressure value of the process gas.

In the above embodiment, the controller 100 executes the processing displayed on the operation unit 15C as the first and second notifications of the present disclosure, but the present invention is not limited thereto. For example, the controller 100 may execute the first notification and the second notification by lighting a display lamp such as an LED, or by emitting a warning sound from a speaker.

The power supply unit 15A and the gas supply unit 15B may be devices different from the control box 15.

In addition, the power cable 16 is preferably covered with a flame-retardant material.

Description of the reference numerals

10 plasma device, 15A power supply section (power supply device), 15B gas supply section (gas supply device), 16 power cable, 16C ground cable, 33 electrodes, 100 controller (control device), 110 electrical leakage detection device, 113 pressure sensor (pressure detection device), 145 shield member, TH1 maximum threshold (second threshold), TH2 upper threshold (first threshold), TH3 lower threshold (first threshold), TH4 minimum threshold (second threshold).

Claims

1. A plasma device is provided with:

an electrode that generates plasma by discharge;

a power supply device that generates power to be supplied to the electrode;

a power cable that supplies the power from the power supply device to the electrode;

a leakage detection device that detects a leakage current of the power cable; and

and a control device that executes a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and executes a second notification based on a result of comparing the leakage current with a second threshold value.

2. The plasma apparatus according to claim 1,

the first threshold value includes an upper threshold value that is larger than a current value of the leakage current detected by the leakage current detecting device in a state where plasma is normally generated,

the second threshold comprises a maximum threshold greater than the upper threshold,

the control device notifies the possibility of leakage of the power cable as the first notification when the current value of the leakage current is equal to or greater than the upper threshold, and notifies the disconnection of the power cable as the second notification when the current value of the leakage current is equal to or greater than the maximum threshold.

3. The plasma apparatus according to claim 1 or claim 2,

the plasma device is provided with:

a gas supply device for supplying a process gas for plasma irradiation; and

a pressure detecting device that detects a pressure of the process gas supplied from the gas supplying device,

the control device executes the first notification and the second notification based on the pressure value of the process gas detected by the pressure detection device and the current value of the leakage current.

4. The plasma apparatus according to claim 3,

the first threshold value includes a lower threshold value that is smaller than a current value of the leakage current detected by the leakage current detecting device in a state where plasma is normally generated,

the second threshold comprises a lowest threshold that is less than the lower threshold,

when the supply of power to the electrode is started, the control device notifies an abnormality that no plasma is irradiated as the second notification when the current value of the leakage current is equal to or less than the minimum threshold value and the pressure value of the process gas detected by the pressure detection device does not increase to a predetermined pressure value,

when the current value of the leakage current is equal to or less than the minimum threshold value and the pressure value of the process gas detected by the pressure detection device has increased to a predetermined pressure value when the supply of the electric power to the electrode is started, the control device notifies an abnormality related to the leakage detection device as the second notification.

5. The plasma apparatus of claim 4,

the control means notifies, as the first notification, an abnormality that no plasma is irradiated when the current value of the leakage current is equal to or less than the lower threshold and the pressure value of the process gas detected by the pressure detection means is reduced to a predetermined pressure value during plasma irradiation after plasma irradiation is started,

in the plasma irradiation period after the start of the plasma irradiation, when the current value of the leakage current is equal to or less than the lower threshold and the pressure value of the process gas detected by the pressure detection device is not reduced to a predetermined pressure value, the control device notifies an abnormality related to the leakage current detection device as the first notification.

6. The plasma apparatus according to any one of claims 1 to 5,

the plasma device is provided with:

a conductive shield member that shields the power cable; and

a ground cable grounding the shielding member,

the leakage current detecting device detects the leakage current flowing through the ground cable.